Mononuclear six-coordinated Ga(III) complexes: A comprehensive survey

Given the commercial availability of 68Ge–68Ga generators, in principle analogous to the worldwide utilized 99Mo–99mTc generator, it is surprising that few 68Ga agents have been developed beyond basic research toward clinical application. The use of the unconventional 68Ga positron emitter would allow for a cost-effective production of 68Ga radiotracers far from a cyclotron facility. Moreover, the use of 67Ga radiopharmaceuticals for imaging studies, and the application of non-radioactive gallium compounds in the treatment of important disorders, including a number of cancer and infectious diseases, make studies on trivalent Ga coordination chemistry attractive for the design of novel gallium-based drugs. The aim of this review is to survey the reported crystal data of six-coordinated Ga(III) complexes in order to gain information to be used in the design of novel Ga complexes of medicinal interest.